CVE-2026-88779: Citrix NetScaler Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability
- Is it exploited?
Yes. CISA added it to the Known Exploited Vulnerabilities catalog on 4 Oct 2026, the same day the CVE record was published.
- How likely is exploitation in the next 30 days?
- 11.4%
EPSS score, percentile 96 of all scored records
- How severe?
- 8.7 High
CVSS v4.0 base score, given by the CNA
- What should I do?
CISA deadline 7 Oct 2026. Apply mitigations in accordance with vendor instructions … Full text
The CVE record links no vendor advisory, patch or mitigation.
- Which versions are affected?
Affected
- before 14.1-73.41
- before 13.1-64.28
- before 14.1-73.41 FIPS
- before 13.1-37.282
- before 14.1-73.41
- before 13.1-64.28
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.
What to do
Required action, set by CISA
Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
CISA due date for this action: 7 October 2026.
Advisories and patches
The CVE record links no vendor advisory, patch or mitigation.
Linked from CISA's catalog entry
- https://support.citrix.com/support-home/kbsearch/article?articleNumber=CTX697174
- https://community.citrix.com/techzone-blogs/110_security-updates/understanding-and-addressing-cve-2026-88779-in-citrix-netscaler-adc-and-citrix-netscaler-gateway/
- https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk
- https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk
- https://nvd.nist.gov/vuln/detail/CVE-2026-88779
Affected products and versions
As listed in the CVE record.
| Status | Versions |
|---|---|
| Affected | before 14.1-73.41 |
| Affected | before 13.1-64.28 |
| Affected | before 14.1-73.41 FIPS |
| Affected | before 13.1-37.282 |
Versions not listed are: unaffected.
| Status | Versions |
|---|---|
| Affected | before 14.1-73.41 |
| Affected | before 13.1-64.28 |
Versions not listed are: unaffected.
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.
About this vulnerability
Citrix NetScaler ADC (formerly Citrix ADC) and Citrix NetScaler Gateway (formerly Citrix Gateway) contain an improper restriction of operations within the bounds of a memory buffer vulnerability that could allow for a denial of service.
Summary: CISA's KEV catalog, as of 28 Oct 2026.
- CISA added CVE-2026-88779 to its Known Exploited Vulnerabilities (KEV) catalog on 4 Oct 2026.
- CISA's ransomware flag for this entry is "Unknown": no evidence of ransomware use in the catalog, which is not proof of none.
- The due date CISA sets for the required action is 7 Oct 2026.
- The CVE record was published on 4 Oct 2026, the same day it was added to KEV.
- The CVE record carries a CVSS v4.0 base score of 8.7 (High), given by its CNA.
- FIRST's EPSS model puts the probability of exploitation in the next 30 days at 11.4% (percentile 96), as of 28 Oct 2026.
- CISA's SSVC assessment in the CVE record: exploitation active, automatable yes, technical impact partial.
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026. About the data.
Description
Memory overflow vulnerability leading to Denial of Service
Vulnerability in NetScaler ADC and NetScaler Gateway. This issue affects ADC: before 14.1-73.41, before 13.1-64.28, before 14.1-73.41 FIPS, and before 13.1-37.282; Gateway: before 14.1-73.41 and before 13.1-64.28.
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.
Weakness
- CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer
CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.
Timeline
| Date | Event |
|---|---|
| 4 Oct 2026 | CVE record published |
| 4 Oct 2026 | Added to CISA KEV |
| 5 Oct 2026 | CVE record last updated |
| 7 Oct 2026 | CISA due date for the required action |
References
More exploited Citrix vulnerabilities
- CVE-2026-88771: Citrix NetScaler Improper Input Validation Vulnerability
- CVE-2026-88772: Citrix NetScaler Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability
- CVE-2026-19490: Citrix NetScaler Authentication Bypass Using an Alternate Path or Channel Vulnerability
- CVE-2026-8452: Citrix NetScaler ADC and NetScaler Gateway Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability
- CVE-2026-3055: Citrix NetScaler Out-of-Bounds Read Vulnerability
- CVE-2025-7775: Citrix NetScaler Memory Overflow Vulnerability